1. Field of the Invention
Aspects of the present invention relate to an actuator for a holographic information storing apparatus.
2. Description of the Related Art
Holographic information storing technologies have been focused on in recent times. Holographic information storing methods use holograms to store information in polymer materials, or in materials comprising mineral crystals, which are sensitive to light that forms of an optical interference pattern. The optical interference pattern is formed by using two coherent laser beams. The optical interference pattern formed by interference between a reference laser beam and signal laser beam that may have difference phases. The interference pattern causes a chemical or physical change in a light-sensitive storage medium and is thereby recorded in the storage medium. To reproduce information from the recorded interference pattern, the reference laser is radiated onto the light sensitive storage medium and diffracts off of the interference pattern, so that the signal light can be reconstructed to reproduce the recorded information.
Such holographic information storage technologies include volume holography methods that record and reproduce information in a page unit, by using volume holography, and micro-holography methods that record and reproduce information in single bits, by using micro-holography. Although volume holography methods simultaneously process large amounts of information, since an associated optical system needs to be very precisely adjusted, it is difficult for the optical system to be used by general consumers, as an information storing apparatus.
Micro-holography methods form a precise interference pattern, by interfering two concentrated light beams at a focus point, to form interference patterns in a recording layer, along a plane of a storage medium. The recording layers are scanned in a depth direction of the storage medium, thereby three-dimensionally recording information on the storage medium.
In holographic information storing apparatuses, it is very important to precisely control the angle of incidence of the reference laser and the signal laser, with regard to holographic media. In general, holographic information storing apparatuses use a Galvano mirror, which are generally too large to be used in a small-sized optical head. When holographic information storing apparatuses uses a micro-electro-mechanical system (MEMS) mirror, the MEMS mirror uses an electrostatic force to provide a small driving force, and thus, its has limited resonance driving frequencies, a limited range of applications, and low precision.